Propeller



A. RUDEBERG Def. 6, 1931.

Patented Get. 6, 1931 aural) STATES PATENT OFFICE ARVID RUDEBERG, OF STOGKHOLM, SWEDEN, ASSIGNOR TO AKTIEBOLAGET MENITOR,

OF STOGKHOLM, SWEDEN PBOPELLER Application filed July 24, 1929, Serial No. 380,487, and in Sweden August 8, 1928.

The present invention relates to a propeller for driving ships and other vessels through water and in which the working surfaces of the blades are convex in the portions next to the hub and concave in the outer portions, so

that the water, into which the concave portions cut, is directed outwards from the propeller shaft, thus preventing an accumulation of water around the propeller shaft and eddyin g movement in the water.

In the accompanying drawings, Fig. 1 shows the propeller seen from astern, and Fig. 2 a longitudinal section of one of the propeller blades. Fig. 3 is a cross section through the convex portion, and Fig. 4 a cross section through the concave portion of the blade.

The central line of the root of theblade is at an angle to the hub in such a manner,

that the leading edge 1 of the blade is in front of the rear edge 2 in the axial direction, and this angle increases towards the outer portion of the blade.

The working surface of the blade is convex up to a certain distance from the hub and then gradually merging into an outer concave portion t, so that a longitudinal section through the working surface shows a line in the form of an 8. The convex portion of 3% the blade is designated by 3.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is v A propeller having a hub and blades extending therefrom, each of said blades having a root portion adjacent the hub of flatly vate form arranged with its longer axis in a plane radial to the axis of the hub and at an acute angle thereto, the outer portion of each blade being convexly curved on one side and concavely curved on the other side in both longitudinal and transverse directions with the curved surfaces merging smoothly into the root portion of the blade whereby the rear surface of the blade is reversely curved from hub to tip in longitudinal section, the front and rear faces of said blade tapering gradually toward each other from hub to tip longitudinally and from the center to the leading and trailing edges transversely,

ARVID RUDEBERG. 

